Scalable Synthesis of Uniform VO2(M) Nanoparticles for High-Performance Thermochromic Films

A facile and scalable sol-gel method combined with post-annealing has been developed to synthesize spherical VO2(M) nanoparticles with a narrow size distribution (average diameter of 100 nm) and uniform morphology. By controlling the concentration of H2O2 solution, oxygen intake, annealing time, and annealing temperature, we achieved precise control over the nanoparticle size and morphology. The resulting flexible films exhibit excellent thermochromic properties, with a reversible color change from blue to transparent at a transition temperature of 68 °C. These films also demonstrate high visible transmittance (>75%) and low solar absorptance (<35%) in both the colored and transparent states, making them suitable for energy-saving applications. This scalable approach offers a promising solution for the large-scale production of VO2(M) nanoparticles with efficient thermochromic properties, paving the way for their use in smart windows, energy-saving devices, and sensors.